@justplaincharlotte, the pattern can be found here. I think the crochet edging is really just for decoration because it's only 2 rows of crochet and it adds sort of a scalloped edge. It's relatively simple. I just learned to crochet not too long ago and I had no trouble with it.
@Olha, I have no idea actually. The girl who wrote the pattern says it's "a decorative way to keep your wine at its optimum temperature at the dinner table." So I'm assuming it keeps it somewhat insulated.